Digestion and Absorbtion 2

Question 1

What does maltose break down into and which enzyme is this reaction catalysed by

Answer 1

Glucose and glucose via maltase

Question 2

What does sucrose isomaltase break down into and which enzyme is this reaction catalysed by

Answer 2

Glucose and fructose by sucrose isomaltase

Question 3

Which two substances are converted to glucose in the liver

Answer 3

Fructose and galactose

Question 4

What does catabolism of glucose produce

Answer 4

ATP

Question 5

What is glycogenesis and where does this process occur

Answer 5

The conversion of glucose to glycogen and occurs in skeletal muscle and liver

Question 6

What is glycogenolysis

Answer 6

The breakdown of glycogen to glucose

Question 7

What is gluconeogenesis

Answer 7

When glucose is made from non-carbohydrate precursors such as fats and proteins

Question 8

What are fully saturated glycogen stores

Answer 8

Where glucose is converted to free fatty acids and stored in adipocytes in the form on truglycerides

Question 9

What are carbohydrates broken down by

Answer 9

Salivary and pancreatic amylase and brush border enzymes in the SI

Question 10

What is glucose anabolism

Answer 10

Glucose storage and release, formation of glucose from proteins and fats, excess glucose stored as fat

Question 11

Which cells rely almost entirely on glucose

Answer 11

CNS, retina and germinal epithelium cells

Question 12

What are normal fasting blood glucose levels

Answer 12

3.5-7.5mmol-1

Question 13

What is the predominant tissue in responding to reduced/ elevated blood glucose levels

Answer 13

The liver

Question 14

What is persistently high blood glucose levels called

Answer 14

Hyperglycaemia

Question 15

What is persistently low blood glucose levels called

Answer 15

Hypoglycaemia

Question 16

What happens if blood glucose levels fall below 3mmol-1?

Answer 16

Loss of conciousness (coma)

Question 17

What happens if blood glucose levels rise above 10mmol-1?

Answer 17

Glucose would appear in the urine, pH of blood would fall lead to coma

Question 18

What happens if there are inadequate levels of glucose in the blood

Answer 18

Cells immediately shift to the catabolism of fats for energy

Question 19

What happens if starvation occurs

Answer 19

Proteins are also used for energy after carbohydrate and fats are depleted

Question 20

Which factors influence blood glucose levels

Answer 20

When eating takes place/ type of food eaten. The amount of physical and mental activity. The presence of hormones

Question 21

Which two hormones are involved in the short term regulation of blood glucose levels

Answer 21

Insulin and glucagon

Question 22

Which 4 hormones are involved in the long term regulation of blood glucose levels

Answer 22

Adrenaline, glucocorticoids, growth hormones, thyroid hormones.

Question 23

What is the glycaemic index (GI) and what does it show

Answer 23

It is a rating system for foods containing carbohydrates and shows us how rapidly each food affects blood glucose levels (when that food is eaten on its own)

Question 24

What are acniar cells and what do they secrete

Answer 24

They are in the pancreas and are part of the exocrine system so secrete digestive enzymes

Question 25

What percentage of the pancreas is made up of Islet of Langerhans

Answer 25

2%

Question 26

Which three types of cells is the Islet of Langerhans made up of

Answer 26

Alpha, beta and delta

Question 27

How much of the islet of Langerhans consists of alpha cells

Answer 27

20%

Question 28

What do alpha cells secrete

Answer 28

Glucagon

Question 29

How much of the islet of Langerhans consists of beta cells

Answer 29

75%

Question 30

What do beta cells secrete

Answer 30

Insulin

Question 31

How much of the islet of Langerhans consists of delta cells

Answer 31

5%

Question 32

What do delta cells secrete

Answer 32

Somatostatin

Question 33

How long is insulin's half-life and what impact does this have on it's regulation of glucose

Answer 33

Insulin has a 5 minute half-life which means that it provides short term regulation

Question 34

What type of protein is insulin

Answer 34

Globular

Question 35

How many amino acids is insulin made from

Answer 35

51 amino acids

Question 36

What does insulin respond to

Answer 36

High blood sugar levels

Question 37

Which hormone responds to high blood sugar levels

Answer 37

Insulin

Question 38

What impact does raised blood glucose levels have on cells in the Islets of Langerhans

Answer 38

Raised plasma glucose levels results in depolarisation of the beta cells

Question 39

How long after a meal does plasma glucose reach max levels

Answer 39

Approximately 60 minutes after

Question 40

Which elicits a greater response- oral glucose or intravenous glucose

Answer 40

Oral glucose

Question 41

What do gastrointestinal hormones 'incretins' do

Answer 41

They enhance beta cell response to glucose

Question 42

What are the 6 actions of insulin

Answer 42

1. Major targets= liver, adipose tissue and muscle mass 2. Increases glucose uptake by cells 3. Stimulates liver to convert glucose into glycogen (glyconeogenesis) 4. Inhibits gluconeogenesis 5. Stimulates excess glucose to be converted into fat (lipogensis) 6. Blood glucose levels drop

Question 43

What is important to note about the CNS and insulin

Answer 43

Glucose uptake by the CNS is independent of insulin

Question 44

Which is the most potent hyperglycaemic hormone

Answer 44

Glucagon

Question 45

How many amino acids is glucagon made of

Answer 45

29 amino acids

Question 46

What is the half life of glucagon

Answer 46

6 minutes

Question 47

Describe the actions of glucagon in relation to insulin

Answer 47

The actions of glucagon directly oppose insulin

Question 48

Why is glucagon secreted

Answer 48

In response to lowered plasma glucose to raise glucose levels

Question 49

Which hormone inhibits glucagon secretion

Answer 49

Insulin

Question 50

What are the nine actions of glucagon

Answer 50

1. If blood glucose falls to dangerous levels the alpha cells release glucagon 2. Glucagon exerts its effects on carbohydrate. fat and protein metabolism 3. The major target of glucagon is the liver 4. Glucagon converts glycogen into glucose (glycogenolysis) 5. It inhibits glycogen synthesis 6. It activates amino acid uptake and gluconeogenesis 7. It increases lipolysis 8. It provides a ready supply of metabolic substances 9. It enables glucose to be spared for the CNS

Question 51

Changes in plasma glucose that occur during fasting then glucose rich meal

Answer 51

First 90 minutes= absorptive state of metabolism, insulin dormant 3-4 hours= post absorptive state of metabolism, glucagon dominant

Question 52

Which hormones apart from insulin and glucagon are involves in the regulation of plasma glucose

Answer 52

Adrenal glucocorticoids, growth hormone, catecholamines, thyroid hormone

Question 53

What functions do the hormones other than insulin and glucagon do

Answer 53

Maintain glycogen stores, stimulate gluconeogenesis, stimulate the metabolism of fatty acids and proteins. They play a significant role during prolonged fasting and conserve glucose for the CNS

Question 54

What 2 metabolic effects does stomatostain have

Answer 54

1. Suppresses glucagon release from alpha cells | 2. Suppresses release of insulin, pituitary tropic hormones, gastrin and secretin

Question 55

What 2 metabolic effects does epinephrine (adrenaline) have

Answer 55

1. Enhances release of glucose from glycogen | 2. Enhances release of fatty acids from adipose tissue

Question 56

What 2 metabolic effects does cortisol have

Answer 56

1. Enhances gluconeogenesis | 2. Antagonises insulin

Question 57

What 2 metabolic effects does ACTH have

Answer 57

1. Enhances release of cortisol | 2. Enhances release of fatty acids from adipose tissue inhibiting uptake by extrahepatic tissues

Question 58

What metabolic effect does growth hormone have

Answer 58

Antagonises insulin, inhibiting uptake of extrahepatic tissues

Question 59

What 2 metabolic effects does thyroxine have

Answer 59

1. Enhances release of glucose from glycogen | 2. Enhances absorption of sugars from intestine

Question 60

Which is the only hormone that lowers blood glucose levels

Answer 60

Insulin

Question 61

What effect do all hormones (apart from insulin) have on blood glucose levels

Answer 61

They raise blood glucose levels

Question 62

What is diabetes mellitus

Answer 62

A condition in which the body either does not produce enough, or does not properly respond to insulin or both

Question 63

What are the 10 symptoms of diabetes mellitus

Answer 63

1. Always tired 2. Always hungry 3. Sexual problems 4. Sudden weight loss 5. Wounds that won't heal 6. Vaginal infections 7. Numb/ tingling hands or feet 8. Always thirsty 9. Frequent urination 10. Blurry vision

Question 64

What are the other names for Type 1 diabetes

Answer 64

'Juvenile' diabetes/ insulin dependent diabetes mellitus (IDDM)

Question 65

What are the other names for Type 2 diabetes

Answer 65

'Adult onset' diabetes, noninsulin dependent diabetes mellitus (NDDM)

Question 66

Why is type 1 diabetes an organ specific immune disorder

Answer 66

It leads to the destruction of pancreatic beta cells resulting in the complete loss of insulin secretion

Question 67

What 4 pros does exercise have in relation to diabetes risk

Answer 67

1. Decreased insulin resistance 2. Decreased risk of obesity and T2DM 3. Exercise may enhance insulin's binding to receptors on the muscle fibre 4. Thyfault and Booth 2011- increased sitting time leads to a reduction in insulin sensitivity

Question 68

What is type 2 diabetes strongly linked to

Answer 68

Obesity

Question 69

What is type 2 diabetes caused by

Answer 69

A reduction in pancreatic insulin or an increasing failure of tissues to respond to insulin

Question 70

How can type 2 diabetes be controlled

Answer 70

Through diet

Question 71

What is temporary glycaemia

Answer 71

Benign and asymptomatic

Question 72

What does long term glyceamia lead to

Answer 72

Increased secretion of glucagon (insulin suppression), increase in glycogen breakdown, increase in rate of gluconeogenesis and increased lipolysis. Leads to further raising of blood glucose levels

Question 73

What are the 3 consequences of hyperglycaemia

Answer 73

Polyuria, polydipsia, polyphagia

Question 74

What is polyuria

Answer 74

Frequent and excessive urination. Osmotic pressure due to glucose in the urine